There are a number of laser leveling devices which are currently in the marketplace. One of such devices is described hereinabove in the above referenced U.S. patent. This device has multiple advantages, however, a number of enhanced features can be added in order to expand the functionality of that device.
A. Angle Measurement
The following describe an invention relating to angle measurement. Many users of a leveling system such as described in the above patent would like the enhanced ability of the level to measure the angle turned by the base unit during operation. This would ease the layout of things like foundation walls, where the contractor could put a leveling system at one corner and from there lay out two walls of the foundation both level and at the correct angles.
To be most useful in these applications, an angle resolution and accuracy of about 0.1xc2x0 are desirable, and the readout should be made at the remote unit which can be a remote control or a target if desired. While the above leveling system contains an encoder, it is mounted on the motor shaft, and there can be backlash in the system such that this encoder may not meet the accuracy specification. In addition, the radio link used is one-way only, and cannot be simply modified to allow display of the angle on the remote control. The invention disclosed has two aspects: those relating to the means for measuring the angle turned by the Base unit, and those relating to display of the angle information on the Remote control unit.
B. Distance Measurement
The following describe an invention relating to range measurement. Many users of a leveling system such as described in the above patent would like the enhanced ability of the level to measure the distance from the Base to the spot from which the beam reflects (either a wall, stud, or the Remote unit itself). In addition to the distance-measurement apparatus disclosed below, the method of transmitting data from the Base (where the distance measurement is actually made) to the Remote (where the data is needed) can use modulation of the laser beam, as disclosed with angle measurement. For the intended application, a distance resolution and accuracy of about 0.2 inches is desirable, independent of distance over the range form 8 to 100 feet.
Additional features, objects and advantages of the invention can be obtained from a review of the detailed description of the preferred embodiment, the claims, and the figures.